Over the past 50 years the United States has used nuclear energy for military purposes and power generation. This has resulted in the establishment of numerous facilities engaged in the production, research, development and testing of nuclear materials. Now the nation must deal with the environmental consequences of the radioactive materials that were generated.
Over forty million tons of soil and debris are contaminated with radioactive waste. This extends to about 1.7 trillion gallons of groundwater in some 5,700 distinct plumes. Hazardous and radioactive waste at more than 120 sites in 36 states and territories must be characterized, treated and disposed of.
Uranium exists in contaminated water and sediments as the highly water soluble uranyl dication [UO2]2+ ion. The uranyl dication is very mobile at these sites, able to travel in solution through the groundwater. Currently there are no techniques that will irreversibly bind the uranyl dication ion and prevent its dispersion in nature.
The present invention relates to the use of boron reagents to bind the uranium and precipitate it from the contaminated water. This allows, for example, the uranium to be collected in sludge ponds where it can be stored or collected for safe disposal or storage. Alternatively, the boron reagents may be used to precipitate the uranium on site and left in place. The precipitate that forms between the boron reagent and uranium will not release the uranium back into the water. Advantageously, the uranyl dication is effectively removed from the groundwater so that it cannot spread out into the environment. Thus, the present invention effectively prevents further environmental damage resulting from uranium contamination.